Composite electrolyte and solid-state battery containing same

A preparation method of composite electrolyte, comprising:

• (1) providing a sulfide electrolyte and a functional additive material, mixing them uniformly, and dispersing them in a weak polar solvent to form an initial mixed solution;
• (2) subjecting the initial mixed solution to heat treatment to remove the weak polar solvent to obtain a premixed composite material;
• and
• (3) mixing the premixed composite material and a polymer electrolyte through ball milling to obtain a composite electrolyte;
• wherein
• the composite electrolyte comprises the sulfide electrolyte, the polymer electrolyte, and the functional additive material, wherein the functional additive material is selected from one or more polymers represented by the following structural formula (1):
• R1—O—R2-A-X formula (1), wherein R1 represents a main chain of the polymer, and —O—R2-A-Z represents a side chain of the polymer,
• R1 is selected from at least one of polyvinyl main chain group, polypropylene main chain group, polyacrylate main chain group, polyvinylcarbonate main chain group, polyacrylonitrile main chain group, and polystyrene main chain group;
• R2 is a straight-chain or branched alkyl group with 3-10 carbon atoms;
• A is selected from at least one aromatic hydrocarbon group of benzene group, biphenyl group, triphenyl group, naphthalene group, anthracene group, phenanthrene group, and pyrene group;
• and
• X is selected from at least one of halogen atom, mercapto group, hydroxyl group, amine group, and aldehyde group.